Award details

Natural regulation of adult neuronal recruitment: comparing food-hoarding and non-hoarding songbirds.

Reference	BB/C006186/1
Principal Investigator / Supervisor	Dr Tom Smulders
Co-Investigators / Co-Supervisors
Institution	Newcastle University
Department	Sch of Biology
Funding type	Research
Value (£)	307,624
Status	Completed
Type	Research Grant
Start date	01/07/2005
End date	30/09/2008
Duration	39 months

Abstract

The discovery of adult neurogenesis in vertebrate brains has led to a watershed of research trying to use it and control it for clinical purposes. Part of this research is into how neurogenesis can be regulated (especially upregulated), in order to repair damaged brain areas, whether by trauma or a neurodegenerative condition. Most of the research in this area is conducted in rats, and they show an increase in incorporation of new neurons into the dentate gyrus of the hippocampus when exposed to enriched environments, hippocampally-dependent learning tasks, or increased physical activity. The problem with this research is that the increase in neurogenesis is from a baseline of environmentally impoverished conditions: traditional rat housing in plastic cages. Therefore, although this research clearly shows that impoverished conditions downregulate neurogenesis in the rat brain, it does not necessarily show that the rats of new neuron incorporation could be unregulated from normal baseline in humans, who routinely experience a very complex environment. We address this problem by investigating neurogenesis in animals living in their natural habitat. In the proposed project, we will investigate the seasonal regulation of neurogenesis in two brain areas in songbirds. Most temperate songbird species show seasonal variation in their singing behaviour, singing more during the breeding season. Leading up to that time, more new neurons are incorporated and survive in nucleus HVC of the song system than do at other times of year, resulting in a larger nucleus with more neurons. In food-hoarding songbirds, such as black-capped chickadees and willow tits, food-hoarding behaviour also varies seasonally. Unlike singing behaviour, it is most intense in the autumn. We have shown before that during this time of year the chickadee hippocampus is larger, containing more neurons than at other times of the year. In the proposed project, we will investigate the regulation of neuronal incorporation into both the hippocampus and nucleus HVC in the same birds. We will describe the seasonal behaviour cycle of hoarding and singing in food-hoarding willow tits in the field in northern Finland. In this study, we will determine whether seasonal changes in neurogenesis in the hippocampus of willow tits are related to food-hoarding, by comparing them to the non-hoarding closely-related great tit. We will determine whether the increase in cell number starts before or after the onset of the seasonal hoarding peak, and whether the net increase in neuron number is caused by an increase in cell division, or a decrease in cell death of the newly generated neurons. We will also start exploring the neuroendocrinological and molecular mechanisms underlying the seasonal regulation of neurogenesis in this species. Because the molecular mechanisms underlying neuronal incorporation in both hippocampus and HVC may be similar, but need to be regulated differently at different times of the year, we predict that there will be an evolutionary trade-off in the food-hoarding birds, decreasing the regulation of new neurons in HVC because evolutionary pressures to regulate it in hippocampus are stronger. Non-hoarding great tits are then predicted to show regulation of neurogenesis in HVC, but not in the hippocampus. In summary, this study will start exploring in detail the regulation of neurogenesis in different brain areas at different times of the year in wild birds. The combination of field ecology, neuroanatomy and neuroendocrinology will allow us to address questions of both function and mechanism with regard to this regulation.

Summary

unavailable

Committee	Closed Committee - Animal Sciences (AS)
Research Topics	Neuroscience and Behaviour
Research Priority	X – Research Priority information not available
Research Initiative	X - not in an Initiative
Funding Scheme	X – not Funded via a specific Funding Scheme

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